Can you help with this deployment question?

My fiance got back from AIT July 31st. He made it to his unit on Aug 4th. They informed him that he may be deployed. He would go to 2wks at Camp Shelby, 2wks Kuwait, and then 6 months in Iraq. Thing that I need to know about is, they told him on the 5th that the holding company as of now is full. The holding company before him that was suppose to ship out July 31st didn't because it was full then as well. So if indeed they are full this time around what happens? His unit comes back in 6 months so then what? Thanks A lot!